The absence of consent is determined on a subjective standard at the time the touching occurs. It is a question of fact determined by the trier-of-fact based on the entirety of the circumstances and the credibility of the victim.[1]

Under s. 265(3), all forms of assault, including sexual assault under 271, 272, and 273[2] cannot be consented when the following exists:

s. 265...Consent
(3) For the purposes of this section, no consent is obtained where the complainant submits or does not resist by reason of

(a) the application of force to the complainant or to a person other than the complainant;

(b) threats or fear of the application of force to the complainant or to a person other than the complainant;

A consensual fight is not an assault as the parties are consenting to the physical contact. [3] Consent can be negated or vitiated where the force causes bodily harm and was intended to be caused.[4] Thus, where serious bodily harm was intended and caused, there can be no consent.[5] The necessary mens rea requires that the force be applied recklessly and the risk of bodily harm was objectively foreseeable.[6]

While normally a person cannot consent to an assault that intends to cause bodily harm, there is an exception to this for sports where the conduct is part of the norms of the particular sport.[1] Thus sports players may consent to some bodily harm necessarily incidental to the sport. However, conduct that is deliberately for the purpose of inflicting injury will not be protected.[2]

There is a degree of implied consent in certain social interactions such as domestic partnerships.[1]

Consent can be used in a limited fashion for a defence to a domestic assault. There must be virtual no injury to the victim. Any injury that occurs can only be justified as an accident and not an intentional assault.

Intentional force intended to cause bodily harm automatically negate any consent.[2] Courts have highly resistant to recognizing consent to an assault between partners.[3]

Meaning of “consent”
273.1 (1) Subject to subsection (2) and subsection 265(3), “consent” means, for the purposes of sections 271, 272 and 273, the voluntary agreement of the complainant to engage in the sexual activity in question.Where no consent obtained
(2) No consent is obtained, for the purposes of sections 271, 272 and 273, where

(a) the agreement is expressed by the words or conduct of a person other than the complainant;

(b) the complainant is incapable of consenting to the activity;

(c) the accused induces the complainant to engage in the activity by abusing a position of trust, power or authority;

(d) the complainant expresses, by words or conduct, a lack of agreement to engage in the activity; or

(e) the complainant, having consented to engage in sexual activity, expresses, by words or conduct, a lack of agreement to continue to engage in the activity.

Subsection (2) not limiting
(3) Nothing in subsection (2) shall be construed as limiting the circumstances in which no consent is obtained.
1992, c. 38, s. 1.Where belief in consent not a defence
273.2 It is not a defence to a charge under section 271, 272 or 273 that the accused believed that the complainant consented to the activity that forms the subject-matter of the charge, where

(a) the accused’s belief arose from the accused’s

(i) self-induced intoxication, or

(ii) recklessness or wilful blindness; or

(b) the accused did not take reasonable steps, in the circumstances known to the accused at the time, to ascertain that the complainant was consenting.

If the trial judge believes the complainant subjectively did not consent, the Crown has proved the absence of consent. The accused’s view of the complainant’s conduct is not relevant to whether the actus reus has been established. [1]

If a victim is unconscious then the crown may prove lack of consent by circumstantial evidence. [2]

While not required, for such evidence to be probative, some expert evidence is often necessary. [3]

As for capacity to consent, courts can infer a lack of capacity where there is direct evidence that:[4]

the complainant was extremely intoxicated;

the complainant was asleep or unconscious when the sexual touching commenced; or

the complainant was asleep or unconscious during all of the sexual touching (B.S.B., supra at para. 45).

The capacity to consent requires more than simply the “baseline physical functions”.[1]

Drunkeness is not the same as incapacity.[2] Poor decision making, memory loss, or loss of inhibition or self-control due to alcohol does not negate consent.[3] An intoxicated complainant may still have the ability to consent.[4]

Where alcohol may have vitiated consent, it may be best established by way of expert evidence.But it is not necessary as a matter of law.[5]

Consent may be vitiated by abusing a position of trust, power or authority. [6]

However, any threats or abuse that occurs after the event cannot go towards vitiation of consent.[7]

The defence of honest but mistaken belief of consent creates a third alternative to the choice between whether the alleged victim consented to the sexual contact.

The defence is available where there is evidence of a "denial of consent, lack of consent or incapacity to consent" which is interpreted as consent, as well as "evidence of ambiguity or equivocality" showing the possibility of mistaken belief without being wilfully blind or reckless.[1]

Thus, the defence requires:

evidence that the accused believed the complainant was consenting;

evidence that the complainant in fact refused consent, did not consent, or was incapable of consenting; and

evidence of a state of ambiguity which explains how lack of consent could have been honestly understood by the defendant as consent, assuming he was not wilfully blind or reckless to whether the complainant was consenting, that is, assuming that he paid appropriate attention to the need for consent and to whether she was consenting or not.

Where "deception causes a misunderstanding as to the nature of the act itself there is no legally recognized consent because what happened is not that for which consent was given"[1]Consent that is not based on a knowledge of the significant relevant factors in not valid.[2]

There are however sex acts involving persons under 18 years of age that are not criminal. Typically, they can be permitted where there is consent. The key rules are essentially as follows:

Persons who are 12 or 13 can consent to sex with persons no more than two years their elder and not in a position of trust (s150.1(2))

Persons who are 14 or 15 can consent to sex with persons no more than five years their elder and not in a position of trust. Or they can consent if married. (s150.1(2.1))

Persons aged 16 and above can consent as an adult.

Consent no defence
150.1 (1) Subject to subsections (2) to (2.2), when an accused is charged with an offence under section 151 or 152 or subsection 153(1), 160(3) or 173(2) or is charged with an offence under section 271, 272 or 273 in respect of a complainant under the age of 16 years, it is not a defence that the complainant consented to the activity that forms the subject-matter of the charge.Exception — complainant aged 12 or 13
(2) When an accused is charged with an offence under section 151 or 152, subsection 173(2) or section 271 in respect of a complainant who is 12 years of age or more but under the age of 14 years, it is a defence that the complainant consented to the activity that forms the subject-matter of the charge if the accused

(a) is less than two years older than the complainant; and

(b) is not in a position of trust or authority towards the complainant, is not a person with whom the complainant is in a relationship of dependency and is not in a relationship with the complainant that is exploitative of the complainant.

Exception — complainant aged 14 or 15
(2.1) When an accused is charged with an offence under section 151 or 152, subsection 173(2) or section 271 in respect of a complainant who is 14 years of age or more but under the age of 16 years, it is a defence that the complainant consented to the activity that forms the subject-matter of the charge if

(a) the accused

(i) is less than five years older than the complainant; and

(ii) is not in a position of trust or authority towards the complainant, is not a person with whom the complainant is in a relationship of dependency and is not in a relationship with the complainant that is exploitative of the complainant; or

(b) the accused is married to the complainant.

Exception for transitional purposes
(2.2) When the accused referred to in subsection (2.1) is five or more years older than the complainant, it is a defence that the complainant consented to the activity that forms the subject-matter of the charge if, on the day on which this subsection comes into force,

(a) the accused is the common-law partner of the complainant, or has been cohabiting with the complainant in a conjugal relationship for a period of less than one year and they have had or are expecting to have a child as a result of the relationship; and

(b) the accused is not in a position of trust or authority towards the complainant, is not a person with whom the complainant is in a relationship of dependency and is not in a relationship with the complainant that is exploitative of the complainant.

Exemption for accused aged twelve or thirteen
(3) No person aged twelve or thirteen years shall be tried for an offence under section 151 or 152 or subsection 173(2) unless the person is in a position of trust or authority towards the complainant, is a person with whom the complainant is in a relationship of dependency or is in a relationship with the complainant that is exploitative of the complainant.
...
R.S., 1985, c. 19 (3rd Supp.), s. 1; 2005, c. 32, s. 2; 2008, c. 6, ss. 13, 54.

Consent Under the Age of 16
Consent cannot be used where the complainant is under the age of 16 except in very limited circumstances. (s.150.1) The accused can justify consent by establishing that they believed the complainant was at least 16 years old where all reasonable steps to ascertain age was taken.(s. 150.1(4)) However, the onus rests on the Crown to establish beyond a reasonable doubt that the steps were not taken. [1]

An accused can only be found guilty of a sex offence under s. 151, 152, 160, 172.1, 173, 271, 272 or 273 which involves a minor where the accused had an honest belief the complainant was of an age of consent. The crown as part of its case should prove beyond a reasonable doubt that the accused failed to take sufficient steps in all the circumstances to ascertain the complainant's age.

The standard to determine the sufficiency of the steps varies depending on the offence. Offences relying on s. 150.1 require the accused take "all reasonable steps", while offences under s. 172.1(4) require "reasonable steps".

s. 172.1...Presumption re age
(3) Evidence that the person referred to in paragraph (1)(a), (b) or (c) was represented to the accused as being under the age of eighteen years, sixteen years or fourteen years, as the case may be, is, in the absence of evidence to the contrary, proof that the accused believed that the person was under that age.No defence
(4) It is not a defence to a charge under paragraph (1)(a), (b) or (c) that the accused believed that the person referred to in that paragraph was at least eighteen years of age, sixteen years or fourteen years of age, as the case may be, unless the accused took reasonable steps to ascertain the age of the person.
2002, c. 13, s. 8; 2007, c. 20, s. 1; 2008, c. 6, s. 14.

150.1 ...Mistake of age
(4) It is not a defence to a charge under section 151 or 152, subsection 160(3) or 173(2), or section 271, 272 or 273 that the accused believed that the complainant was 16 years of age or more at the time the offence is alleged to have been committed unless the accused took all reasonable steps to ascertain the age of the complainant.Idem
(5) It is not a defence to a charge under section 153, 159, 170, 171 or 172 or subsection 212(2) or (4) that the accused believed that the complainant was eighteen years of age or more at the time the offence is alleged to have been committed unless the accused took all reasonable steps to ascertain the age of the complainant.Mistake of age
(6) An accused cannot raise a mistaken belief in the age of the complainant in order to invoke a defence under subsection (2) or (2.1) unless the accused took all reasonable steps to ascertain the age of the complainant.
...
R.S., 1985, c. 19 (3rd Supp.), s. 1; 2005, c. 32, s. 2; 2008, c. 6, ss. 13, 54.

"Reasonable steps" must be assessed in context and will turn on the specific circumstances of the case.[1] Both reasonable steps and "all reasonable steps" must be assessed on the basis of an objective and reasonable person.[2]

Under s. 150.1, "all reasonable steps" is a "due diligence defence".[3] The test is whether the steps ones that “a reasonable person would take in the circumstances” to ascertain a complainant’s age.[4]